Unfortunately, Last day i forgoted my account password for my laptop acer, linux os.
I can't boot the system. Pls someone help me :) i very need it to unlock password..
Cheers...

do you know the root password for the linux? if so wait till the system boots up then press ctrl+alt+f1 to f6 (any) to get a command shell.
when you get the command shell login as root then giving root password. once you get the prompt then type
passwd <username>
it will ask for the password of your user.

passwd command changes the password. only root can change password for other users. becareful if you give the command without username you will be changing the password of root.